Recently, the techniques for providing 3D stereo images on a screen rapidly increase in various fields such as movies, broadcasting, game or the like. Generally, the terms “3D image” and “3D stereo image” are confusedly used, but strictly speaking, these terms are entirely different from each other. The term “3D image” represents a planar image showing all of x, y and z axes on a general 2D display, and the term “3D stereo image” represents an image implemented on a display to allow a user to feel a depth and a stereoscopic space sense.
Regarding cameras for stereo images to make a 3D stereo image, an image is photographed by two cameras simultaneously and then displayed so that a user may feel perspective and recognize stereo. In this regard, FIG. 1 schematically shows a conventional 3D stereo camera system 2. In order to photograph a stereo image by using cameras, a target 1 is photographed by using two cameras 3a, 3b by using the same principle as both eyes which comprehend prospective of an object. After two right and left cameras 3a, 3b are mounted to a rig (a device for arranging cameras vertically and horizontally and fixing them) and photograph a target 1, images photographed by the right and left cameras 3a, 3b are overlaid to make a stereoscopic image. At this time, two cameras should be synchronized for their exposure, focusing, shutter speed or the like, and for this, the cameras 3a, 3b are respectively controlled by a controller 4.
A thermal imaging camera is a device for imaging infrared rays present in the natural world and having a very long wavelength of 1 μm to 14 μm in comparison to visible rays. Since the thermal imaging camera displays a thermal image, it displays image in a gray level using black and white as well known in the art according to high or low of the thermal energy. Therefore, the thermal image may be misunderstood as a black-and-white image but it contains information for thermal energy. Until now, all kinds of thermal imaging cameras have drawn the thermal image and have been simply used for measuring the presence or movement of a target or measuring temperature or heat distribution.
If the thermal imaging data is displayed as a 3D stereo image, it is possible to obtain more accurate and abundant information about the target. However, there has been no attempt to couple thermal imaging data with 3D stereo image data so far. In order to couple 3D stereo image data and thermal imaging data, various problems should be solved, and the most important problem is that a target should be photographed simultaneously and accurately by using two thermal image cameras with the identical performance. The thermal imaging camera includes a lot of temperature sensor elements, which are also called detectors. However, since individual temperature sensor elements respond to a surrounding temperature and a target temperature in different ways, non-uniformity phenomenon occurs and so images photographed by two cameras may be different. In other words, since detectors of a camera have different gain and offset in the temperature sensor array, thermal images obtained by two cameras become different, and so it is impossible to implement a proper 3D stereo thermal image.
The present disclosure is directed to providing a 3D stereo thermal imaging camera system which may provide a 3D stereo thermal image and distance/depth data by solving problems caused by different element performance of detectors of two thermal imaging cameras.
The present disclosure is also directed to providing a software processing method which allows high-speed frame processing by processing only an image area of interest for the purpose of high-speed data processing.
In one general aspect, the present disclosure provides a 3D stereo image camera system for generating a 3-dimensional (3D) stereo image, which includes: first and second thermal imaging cameras 100a,100b horizontally spaced apart by a predetermined distance to photograph a subject; and a stereo & disparity engine 300 for providing a control signal and a clock signal to the first and second thermal imaging cameras, receiving thermal imaging data from each of the thermal imaging cameras, and calculating disparity data, distance/depth data, and temperature data of the subject from the thermal imaging data.
In addition, in the 3D stereo image camera system, the first thermal imaging camera may operate as a master camera, the second thermal imaging camera may operate as a slave camera, and the reference value relating to the performance of at least one property may be a reference value relating to the master camera.
In the present disclosure described above, since one of right and left thermal imaging cameras has a master function and the other thermal imaging camera has a slave function, a master thermal imaging camera plays a role of providing various references, and the slave camera is adjusted with reference to the reference data of the master camera so that both thermal imaging cameras resultantly have the same performance. Accordingly, since both cameras may ensure the matched performance by based on matched functioning, it is possible to provide a 3D stereo thermal image and distance/depth data. In addition, since a separate camera having a master function may plays a role of various references, two thermal imaging cameras may ensure matched performance and provide a 3D stereo thermal image and distance/depth data.